1、 Programme background
With the extensive use of tower cranes in the construction industry in recent years, all kinds of tower crane operation safety accidents caused by illegal operation and interference and collision of tower cranes occur frequently, resulting in huge loss of life and property. The experience and lessons of safety accidents show that it is necessary to timely and effectively supervise the use process and behavior of tower crane, so as to effectively control the dangerous factors and hidden dangers in the process of equipment operation, and prevent and reduce the occurrence of safety production accidents of tower crane.
2、 Demand analysis
1. Real time monitoring and recording of site operation information, timely and effective supervision of tower crane use process and behavior, can effectively control the risk factors and potential safety hazards in the process of equipment operation, and prevent and reduce the production accidents of tower crane.
2. Track and view the active personnel on the construction site, and provide high-definition image quality to distinguish the characteristics of suspicious personnel, so as to prevent outsiders from entering the construction site to steal construction materials.
3. The cab is composed of a 12 inch LCD monitor, which can watch whether the hook is properly hung and work according to the operation regulations through video.
4. Must ensure that the image is clear, no delay, no compression loss, low cost, simple construction, installation and debugging.
3、 Scheme design ideas
According to the field survey, due to the particularity of the system and environment, the distance between the monitoring center (tower crane cab) and the monitoring point (tower crane hook) is not very far. Because there is a middle building block (hook up and down track movement) when the hook is lifting materials in different directions, the hs-5868n receiving end is installed in the middle of the cross arm, and two external antennas are distributed at both ends of the cross arm of the tower crane, It is 20 meters away from the receiving equipment, so as to achieve a wide range of wireless signal coverage. Whether the front end or the back end of the hook lands, it can achieve line of sight wireless transmission to ensure that the video will not be switched or interrupted.
In the case that wired lines can not be set up, the wireless networking mode is adopted, which has the characteristics of fast networking, low cost, simple installation and debugging, convenient management, and can provide sufficient bandwidth. In this wireless network system, it mainly includes the following parts: front-end camera part: (customized) it is composed of camera, wireless bridge omni-directional antenna ‘protective cover, bracket, 4 pieces of strong magnetic, 3-angle iron frame used to adsorb the upper part of the hook, lithium battery (the hook can’t supply power normally), etc. Wireless network part: composed of point to multipoint wireless bridge hs-5868 wireless access equipment. Monitoring center part: the back-end NVR connects the receiving end equipment with super class 5 network cable, and watches the playback in real time through the 12 inch display.
Editor in charge: GT